Safety device for ladders



Feb. 12, 1924; 1,is3,14s

A. WINKLER SAFETY DEVICE FOR LADDERS Filed NOV. 6. 1922 l f l mgwf WMMPatented Feb. l2, 1924.

IIN-WED? STATES ortica.

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SAFETY DEVICE FOR LADDERS.

Application mea November e, 1922. serial No. 599,417.

To all whom' t may concern.'

Be' it known thatv I, AUGUST WINKLER, a citizen of the Republic ofSwitzerland, residing at Zurich, in the Canton of Zurich, Switzerland,have invented certain new and useful Improvements in Safety Devices forLadders, of which the following is a speciflcation.

It has been previously proposed, in order to secure ladders and maintainthem in position, when placed against a wall or other structure, toprovide feet for the ladderposts or uprights. In one known kind ofantislipping foot for ladders provision is made of a shoe having asocket pivoted thereto and adapted to receive the ladderpost. Theseknown antislipping feet have, however, the drawback either that theladder-post is secured kin the socket by means of an unsafe screw only,or that the socket is not capable of receiving ladder-posts of differentsizes. In another known antislipping `foot the ladder-shoe, thoughdesigned to receive ladder-posts of various dimensions, the posts aredirectly secured to or in the shoes or a part rigidly attached theretoby means of thumb screws, which, every time the ladder is placed in adifferent slanting position, have to be loosened and adjusted again.

It is the object of my invention to avoid all these drawbacks and topermit of an easy, varied and safe application of the improved safetydevice to ladders, with uprights of various sizes.

In the accompanying drawings embodyino' one desirable form of myinvention:

ig. 1 shows a perspective view of the shoe as applied to one of theuprights of a ladder;

Fig. 2 shows a sectional elevation of the same device;

Fig. 3 represents a section through line Y-Z in Fig. 2 the upright beingshown in dotted lines, and

Fig. 4 is a plan view of the shoe as seen from below.

Referring to these drawings, each of the ladder-shoes comprises abase-part 1, the lower face thereof being provided with two or morecylindrical recesses to receive rubber discs 2. The upper portion ofthis basepart is curved and also recessed at the sides, as at 3, inorder to receive the integral fork-shaped members 4 of a top part 5acting in the manner of a supporting member' which is pivoted to andmounted centrally ofthe base-part by means of the said members 4 and abolt 6. Screwed into the ends of the top-part or supporting member andextending into a longitudinally disposed slot 7 thereof are thumb-screws8, the vform of the slot 7 being clearly shown in Figs. 2 and 3. Thisslot serves for the reception of two U-shaped clamping plates 9 which,when the shoe is applied to the upright of a ladder, are made to gripand partly embrace the bottom end of the upright, Fig. 1. The clampingplates are thus capable of a sliding movement in the slot 7 and, when inthe position illustrated in the drawings, prevented from accidentaldetachment by the shouldered-olf lower end 9ZL fitting into thecorrespondingly'formed slot. By means of the thumb-screws 8 the lowerends of the clamping plates 9 may be tightly pressed against the uprightof the ladder, while the upper end of each of the said clamping platesis brought to bear against and made to firmly grip the upright by theaid of a metal hoop 10 and a thumb-screw 11.

If it is desired to fit a ladder with the shoes described, it is merelynecessary to slip the uprights of the ladder between the clamping plates9 and thereafter to tighten the three thumb-screws 8 and 11.

The supporting member 5 and the clamp- .ing plates may be designed andadapted to receive the uprights of ladders of various sizes, the mainfeature of my invention, however, consisting therein, that the pressureor strain on the ladder in any of its positions is always taken up bythe centrally disposed bolt 6 and evenly transmitted to the base-part.The friction of the rubber discs 2 with the ground, as the ,datahereinafter mentioned will show, is

sufficient to take up the horizontal component forces on the uprights.Tests have shown that the angle, at which a ladder fitted with suchshoes may safely be placed relative to the horizontal, is the following:for linoleum or oil-cloth 30, for smooth stone stairs 40, for polishedtile oors 41 for polished inlaid iioors 44, for dry and smooth tiles 47and for wet tiles 51.

It will be easily understood, firstly, that the metal hoop 10 withthumb-screw 11 may be replaced by a simple leather-strap and buckle, andsecondly, that the clampingy plates 9 may altogether be dispensed with,

in which latter ease the top-part or supporting member would beconstructed in the forni of a housing adapted to receive the'bottom endof the upright of the ladder.

Having now fully described my invention what I claim and desire tosecure by Letters Patent is In the herein-described safety device forladders, the combination, With a shoe having reeesses in its flatbottom, and rubber discs in said recesses, of a supporting memberpivoted to and mounted centrally of the shoe and having the form of arectangular frame provided with a longitudinally disposed slot, twoU-shaped clamping plates 15 Within the said slot and cause them totightly 20 ri Variousl sized ladder uprights. g p y AUG. WINKLER.

